An exploratory study of the impact of common land-use policies on air quality

An exploratory simulation model is developed to examine the effects of land-use policies on transportation activities and vehicle emission. It is assumed individuals choose to live among 3 zones in each of two neighboring cities and commute to work by auto. Residential choice is assumed to be the result of optimizing transportation and housing costs. Vehicle emissions are modeled as a function of each city's population, trip length and route capacity. Three scenarios are constructed to investigate the combined effects of land-use policies and other common polices such as rent control and control of land supply measures on changes in vehicle emissions. The results indicate that mixing residential and business uses in one city may result in residential price increases, and thus displace incumbent residents to a neighboring city. The displacement may create a net increase in vehicle emissions if the new route to work is more congestion-prone and has lower capacity than the old route. Displacement, and hence vehicle emissions tend to increase when the price responsiveness of residential demands in both neighboring cities are comparable. We also examine the impacts from two other common polices such as rent subsidies programs and control of land supply. It is found that these policies, if implemented together with land-use polices may exacerbate the displacement of residents to other housing markets. In light of the results, it is important for the policy makers to take into account of residential mobility in evaluating the effectiveness of any land-use policy aimed at reducing vehicle emissions.